By the time of the start of WW II Switzerland had fortified every mountain pass from the outside into their country. This is a small sample of gun batteries we saw everywhere. In addition, the preparation included tunnels and bridges that were set with dynamite ready charges, mined fields, airplane hangars carved out of the sides of mountains and roads set to be used for runways. Also, passes had tank barriers, mines and gun emplacements covering all narrow and wide flatlands.

And, Switzerland was probably the only country in the world that had bomb shelters to accommodate every citizen living there.